superseded: [PATCH qemu-server] cloud-init: activate volume early enough to fix regression with qcow2 on LVM

[Fiona Ebner <f.ebner@proxmox.com>]

superseded-by:
https://lore.proxmox.com/pve-devel/20260812111316.85049-1-f.ebner@proxmox.com/T/

Had forgotten to update the title, since I went for the alternative
approach at first.

Am 12.08.26 um 1:10 PM schrieb Fiona Ebner:
> Since pve-storage commit 05032c5 ("fix #7811: storage: lvm: reject
> allocation on format and volume name mismatch") and its follow-ups,
> cloud-init disks are named with a '.qcow2' extension on LVM storages
> with snapshot-as-volume-chain enabled.
> 
> This causes a regression, because volume_size_info() fails and returns
> undef when the qcow2 volume is not active. When the size cannot be
> determined, commit_cloudinit_disk() function assumes that the disk
> does not yet exist and tries to allocate new disk with the same name,
> which fails.
> 
>  [I] root@pve9a1 ~# qm start 100
>  failed to stat '/dev/lvm/vm-100-cloudinit.qcow2'
>    Rounding up size to full physical extent 8.00 MiB
>  lvcreate 'lvm/vm-100-cloudinit.qcow2' error:   Logical Volume
>   "vm-100-cloudinit.qcow2" already exists in volume group "lvm"
> 
> Fix the issue by checking the existence/size with vdisk_list(), which
> also works for deactivated volumes.
> 
> Activating the volume earlier is an alternative, but would need to be
> inside an eval block that silently ignores failure, since the volume
> might not exist yet, which should not be logged. And in case where the
> qcow2 on LVM volume does exist, but activation fails, there would be
> an attempt to allocate a new volume with the same name, which also
> seems less than ideal. So that approach is a bit hacky.
> 
> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
> ---
>  src/PVE/QemuServer/Cloudinit.pm | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/src/PVE/QemuServer/Cloudinit.pm b/src/PVE/QemuServer/Cloudinit.pm
> index c1311da8..5af6b608 100644
> --- a/src/PVE/QemuServer/Cloudinit.pm
> +++ b/src/PVE/QemuServer/Cloudinit.pm
> @@ -39,7 +39,18 @@ sub commit_cloudinit_disk {
>      my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
>      my $format = checked_volume_format($storecfg, $drive->{file});
>  
> -    my $size = eval { PVE::Storage::volume_size_info($storecfg, $drive->{file}) };
> +    my $volumes = PVE::Storage::vdisk_list($storecfg, $storeid, $vmid, [$drive->{file}], 'images');
> +    if (scalar($volumes->{$storeid}->@*) > 1) {
> +        # just to be sure, since this is the first caller with $vollist outside of the storage tests
> +        print "bug: storage plugin for '$storeid' does not honor \$vollist for list_images()\n";
> +    }
> +    my $size;
> +    for my $volume_info ($volumes->{$storeid}->@*) {
> +        next if $volume_info->{volid} ne $drive->{file};
> +        $size = $volume_info->{size} // $volume_info->{'approximate-size'};
> +        last;
> +    }
> +
>      if (!defined($size) || $size <= 0) {
>          $volname =~ m/(vm-$vmid-cloudinit(.\Q$format\E)?)/;
>          my $name = $1;